I see a potential problem with BlogSnob, depending on your point of view. The premise is that for each ad that your site serves, another site will display an ad about your site. I first thought that this was a cool idea but now I think that it will only help the popular sites become more popular. Some independent site may serve 10 ads and therefore it will get 10 ads in return, but a popular site could serve over a thousand ads in a day and it would recieve a thousand in a day just making it more popular. You could probably even apply the 80/20 rule, 20% of the sites would account for 80% of the ads.